Organisms in the Xevoz Planet are divided into 8 species:
- Neo Sapiens: Science-fiction-themed, near-future humans.
- Meta-Beast: Anthropomorphic animals.
- Sectoid: Giant insects and bugs, frequently larger than humans.
- Hyperfuries: Elemental creatures.
- Biomecha: Almost completely mechanical cyborgs.
- Unnatural: Undead creatures.
- Reptosaur: Reptilian/draconic creatures.
- Arcaster: Originally named Runics. Fantasy-themed, magic-using humans.
Note: Reptosaurs and Arcasters were added in Wave 4.